Like it or not, Microsoft Office 2011 for Mac is the most widely-used office suite for Mac users in the enterprise. While the existing version doesn't support OS X Lion features like Auto Save, Versions, and full-screen mode, MacNN is reporting that Microsoft's Mac Business Unit is hard at work adding those and possibly other features to Office.
Don't expect an update tomorrow, though. According to Microsoft Office team member Pat Fox, the wait for an updated Office 2011 will be "measured in months." If you're a user of Communicator for Mac, you can get an update right now that resolves some crashing issues in Lion. It's available through Microsoft's AutoUpdate, and can also be downloaded from the MS Download Center.
The company also noted that Office for Mac 2004 will never be Lion-compatible, since it was originally written for PowerPC-based Macs. If you're still trying to coax that old copy of Office for Mac 2004 along as you move forward to Lion, it's time to make the upgrade to Office 2011 ... or consider alternatives like Apple's iWork suite.
It will also be fascinating to see if Microsoft decides to bring Office 2011 to the Mac App Store, either in whole or as separate parts à la iWork. Only time will tell.